\begin{tikzpicture}
    \pgfmathsetmacro{\R}{2}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(60:\R){A}
    \tkzDrawCircle[very thick](O,A)
    \tkzDrawSegment(O,A)
    \tkzLabelSegment[left](O,A){$R$}
    \tkzLabelPoints[left](O)

    \tkzDefRegPolygon[center,sides=6,name=P](O,A)
    \tkzDrawPolygon[thick,red](P1,P...,P6)
    \tkzDefMidPoint(P4,P5)  \tkzGetPoint{H}
    \tkzDrawSegment(O,H)
    \tkzLabelSegment[right](O,H){$r_n$}

    \tkzDefRegPolygon[center,sides=12,name=P](O,A)
    \tkzDrawPolygon[thick,blue](P1,P...,P12)
\end{tikzpicture}

